High pressure internal cleaning method and apparatus

ABSTRACT

An improved method and apparatus for flushing the residue from internal surfaces of cavities in, for example, turbine blades. In accordance with one aspect of the invention, provision is made for simultaneously flushing the internal cavities of a plurality of turbine blades, with each blade having a plurality of cavities therein.

CROSS REFERENCE TO RELATED APPLICATIONS

This invention relates to U.S. patent application Ser. No. 10/271,681,now U.S. Pat. No. 7,207,997, entitled Apparatus and Method for CleaningAirfoil Internal Cavities, filed on Oct. 15, 2002, and assigned to theassignee of the present invention and which is incorporated herein byreference.

This is a divisional application of U.S. Ser. No. 10/747,720, filed Dec.29, 2003, now U.S. Pat. No. 7,406,971, the entirety of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates generally to parts, such as turbine blades, thathave internal cavities and, more particularly to a method and apparatusfor cleaning the internal cavities thereof.

In the manufacture or repair of turbine blades of the type used in thehigh pressure turbine of a gas turbine engine, the internal cavities ofthe blade are left with a residue of undesirable foreign material suchas salts, silicone and silk, which must be removed from the internalcavities in order to obtain proper performance therefrom. In addition,the foreign material can collect in corners or other such locationswithin the internal cavities. The usual method of cleaning theseinternal surfaces is to conduct an autoclave or ultrasonic cleaningoperation, followed by a flushing out of the cavities by the use of ahigh pressure washing process.

The flushing process is commonly accomplished by using one or moreprobes to introduce a high pressure flow of a liquid such as water intoone or more of the cavities in order to wash out the undesirableresidue.

The apparatus for positioning the probes with respect to the bladecavity has generally been of two types. The one that has been usedfollowing the autoclave process was that of a single blade being flushedby a pair of probes simultaneously registering with their respectivecavities, after which the probes were retracted and then indexed to thenext blade for the same process.

Another prior art process that has been used after ultrasonic cleaningis that of a fixture having a pair of extended probes that separatelyregister with individual cavities of two different blades. After therespective cavities have been cleaned, the fixture is retracted and thenindexed to adjacent cavities in the same respective blades.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, the apparatus forflushing turbine blades has a plurality of probes that are spaced in theplane in which a plurality of spaced blades are held in place such thata plurality of blades can be simultaneously flushed, and the apparatusalso includes a plurality of probes in a plane in which the individualcavities of a single blade are disposed such that a plurality ofcavities within a single blade can be simultaneously flushed. In thisway multiple cavities and multiple blades can be simultaneously flushedin a single process.

In the drawings as hereinafter described, a preferred embodiment isdepicted; however various other modifications and alternateconstructions can be made thereto without departing from the true spiritand scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross sectional view of a turbine blade asbeing flushed in accordance with the present invention.

FIG. 2 is a perspective view of an apparatus for simultaneously flushinga plurality of blades in accordance with one embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, a turbine blade of the type used in a highpressure turbine of a gas turbine engine is shown to include a rootportion 11 at its one end and airfoil portion 12 at its other end. Theairfoil portion 12 has a leading edge 13, a trailing edge 14, and a endwall 16 opposite the root portion 11, as well as internal walls 17 and18 which collectively define the internal cavities 19, 21 and 22 thatextend generally longitudinally within the internal structure of theturbine blade.

The root portion 11 includes a plurality of serrations 23 on the outerside thereof to facilitate the attachment to corresponding features onthe turbine rotor (not shown), and a plurality of root openings 24, 26and 27 that lead to the internal cavities 19, 21 and 22. When installedand operating, high pressure air is introduced into the root openings24, 26 and 27 so as to flow through the cavities 19, 21 and 22 and toexit out the opening in the trailing edge 14 for purposes of cooling theblade.

During the cleaning process in the factory or repair facility, followingan autoclave and/or ultrasonic cleaning process, a flushing process isapplied to remove various types of undesirable residue from the interiorof the blade by the circulation of high pressure fluid, such as water,through the cavities as indicated by the arrows.

As will be seen, a probe 28 is inserted into the cavity 19 to the extentthat its end openings 29 is just past the radially outer end of theinternal wall 17. A high pressure fluid is then caused to flow throughthe tubular probe 28 and to be discharged from the end 29 such that itflows against the end wall 16 and back through the cavity 21 asindicated by the arrows.

Similarly, a probe 31 is introduced into the cavity 22 to the extentthat it reaches well beyond the radially inner end of the internal wall18. A high pressure fluid, such as water at a pressure of around 10,000psi, is caused to flow from the end 32 of the probe 31, along the cavity22 and out the openings in the trailing edge 14 as shown by the arrows.

Reference is now made to FIG. 2 wherein there is shown apparatus for thesimultaneous flushing of the internal cavities of a plurality of turbineblades.

A blade holder 33 includes a plurality of spaced chucks 34, 36, 37, and38 having serrations for receiving the root portion of the blades 39, 41and 42, therebetween. The blade holder 33 also includes a guide number43 that is disposed transversely across and near the ends of the rootsof the blades 39, 41 and 42. The guide member 43 contains a plurality ofpassages whose axes are aligned with the root openings of the turbineblades as described hereinabove. That is, passages 44 and 46 have theiraxes aligned with respective root openings 24 and 27 of blade 39,passages 47 and 48 have axes that are aligned with respective rootopenings 24 and 27 of blade 41 and passages 49 and 51 have axes that arealigned with root openings 24 and 27 of blade 42.

Disposed opposite the guide member 43 is a manifold 52 which isreciprocally mounted on a base 62 having side guide members 63 and 64and having a central guide member 66, all of which act to maintain thefixed transverse position of the manifold 52 as it is retracted andadvanced along those guide members. Such advancement and retraction maybe accomplished by the manual grasping of a handle 68 and moving themanifold forwardly or backwardly on its base 62. Alternatively, ahydraulic mechanism can be attached to the manifold 52 to advance orretract it along its path by the base 62 and its guide members 63,64 and66.

The manifold 52 is fluidly connected to a high pressure (e.g. 10,000psi) fluid source such as water or the like. On the front side of themanifold 52 there are a plurality of discharge ports 53 extendingoutwardly and fluidly connected to respective probes or probe tubeswhose axes are aligned with the axes of the respective passages in theguide member 43. That is, probe 54 has its axis aligned with the axis ofthe passageway 44, probe 56 has its axis aligned with the axis ofpassage 46, probe 57 has its axis aligned with the axis of passage 47,probe 58 has its axis aligned with the axis of passage 48, probe 59 hasits axis aligned with the axis of passage 49, and probe 61 has its axisaligned with the axis of passage 51.

As will be seen in FIG. 2, with each probe pair associated with a singleturbine blade, one is longer than the other so as to accommodate therequired insertion degrees. The particular probe combinations are uniqueto a particular turbine blade design. Further, the guide member 43, andmost likely the blade holder 33 with its various chucks, are to be usedonly with a particular design of turbine blade since the positioning ofthe turbine blade, the passages in the guide member 43 and the lengthand positioning of the various probes as held by the discharge portmembers 53, must all be closely coordinated. Thus, for any one of thevertically spaced pairs of probes as shown in FIG. 2, only a single typeof blade design may be cleaned with this process. Preferably, each ofthe three vertically spaced pairs is identical and is adapted for thecleaning of identical blade designs.

Considering now the steps in the process of cleaning a plurality ofturbine blades, the manifold 52, is moved to the retracted position withthe probes being to the left of the guide member 43. The blade holder33, with its installed blades, has been moved to a precise positionopposite the manifolds 52 with the reference guide surface 69 acting toprecisely locate the blade holder 33 on its right side, and with thelower guide surface 71 acting as a reference surface to precisely locatethe blade holder 33 in the vertical plane. The manifold 52 and itsextended probes are advanced, with the probes passing through therespective passages in the guide member and into their respectivecavities of the blades. The fluid source 67 is then activated to forcethe high pressure flow of water into the cavities for removing anyresidue from the internal surfaces thereof.

After the cleaning process has been completed the manifold 53 is thenretracted, and the blade holder 33 with its attached blades is thenlifted from its position and moved to a more remote location so that itscleaned blades can be removed from the holder 33 and other blades areinserted therein such that the holder 33 can then be subsequently placedin position abutting the reference guide surface 69 and the lower guidesurface 71 for a repeat of the process.

While the present invention has been particularly shown and describedwith reference to various embodiments as illustrated in the drawings, itwill be understood by one skilled in the art that various changes indetail may be effected therein without departing from the true spiritand scope of the invention as defined by the claims.

1. Apparatus for fluidly flushing the internal cavities of a pluralityof parts, comprising: a fixture for holding a plurality of parts inspaced side-by-side relationship in a first plane, with each part havinga plurality of spaced apart cavities aligned in a plane other than saidfirst plane; a guide member disposed adjacent said fixture and having aplurality of passages formed therein including adjacent passages thatare in a common plane parallel to said first plane and includingadjacent passages that are in a common plane other than said first planeand wherein each of said passages is axially aligned in coincidence withone of said part cavities; a manifold having a plurality of probe tubesextending therefrom with each of said passages being axially alignedwith one of said plurality of probe tubes, said manifold also having afluid source connected thereto for providing pressurized fluid flowthrough each of said probe tubes so as to be discharged from therespective ends thereof; and means for advancing said manifold towardsaid guide member such that for each of said passages and cavities thereis a probe tube which passes through a respective passage and into arespective cavity for flushing internal surfaces thereof; and whereinsome of said probe tubes are of different lengths.
 2. Apparatus as setforth in claim 1 wherein said first plane is substantially normal tosaid plane other than said first plane.
 3. Apparatus as set forth inclaim 1 wherein said guide member is integrally formed with saidfixture.
 4. Apparatus as set forth in claim 1 wherein, within the samepart, the probe tubes being advanced therein are of different lengths.5. Apparatus as set forth in claim 1 wherein said means for advancingsaid manifold also includes means for retracting said manifold when theflushing has been completed.
 6. Apparatus as set forth in claim 1 andincluding a means for removing the said fixture and replacing it withanother fixture.
 7. Apparatus as set forth in claim 6 wherein saidremoving means is operative to remove said fixture along said firstplane.
 8. The apparatus as set forth in claim 1, wherein said parts aregas turbine engine parts.
 9. The apparatus as set forth in claim 8,wherein said gas turbine engine parts comprise turbine blades.